Leg axis correction with ConforMIS iForma™ (interpositional device) in unicompartmental arthritis of the knee

Abstract

Degeneration of the meniscus and the articular cartilage in unicompartmental osteoarthritis of the knee results in progressive deformity of the leg axis.

Navigated lateral unicompartmental knee arthroplasty — Technique and case report

“…Comparative positive results including durable and reliable short-term to mid-term results, even through a medial approach after a mean follow-up time of 5 years, were also shown by another group [23,24]. Current trends in new technologies with use of custom-made interpositional devices or custommade lateral unicompartmental knee replacement also seem to show promising results; however, long-term studies are not yet available [25].…”

The UniSpacer™: correcting varus malalignment in medial gonarthrosis

“…Hemiarthroplasty with metallic interpositional devices, while first described over half a century ago, is also currently experiencing a renaissance as a treatment option for varus unicompartmental OA, the idea being to provide a means of [15]; there are still few reports examining the use of the self-centering UniSpacer™ device in medial gonarthrosis. This study is the first to evaluate clinical and functional results after a minimum follow-up time of five years.…”

“…There are almost no data for interpositional hemiarthroplasty. The study by Koeck et al on the iForma™ implant [15] showed an average postoperative alignment (mTFA) of −0.9°and a mean correction of 3.8°. A significant correlation between extent of correction and thickness of the implant was shown.…”

“…It is available in several thicknesses and adapts to knee kinematics [21]. In contrast to the recently introduced ConforMIS iForma™ knee implant [15], the UniSpacer™ is a self-centering device that is not fixed to any structures ("self-centering"); it is used to correct or minimise varus malalignment in unicompartmental osteo-arthritis of the knee where other procedures are not indicated (Fig. 1).…”

Removal and successful re-implantation of a customized interpositional knee device following an early postoperative infection: A case report

“…Although adverse outcomes have been reported with the re-established interpositional Unispacer™ knee system (Zimmer, Inc), with devastating early failure rates ranging between 20 and 30 percent caused mainly by implant dislocation and persistent pain [7][8][9], No clinical results have been reported so far for the iForma™ interpositional device (ConforMIS, Inc, Burlington, MA, USA), which was used in our case and is customized via magnetic resonance imaging (MRI). Only the reliability of leg axis correction in unicompartmental knee arthritis with this device has been demonstrated [10].…”